Set top terminal (STT) devices are typically deployed in numerous premises throughout subscriber networks that serve numerous households and/or businesses over a wide region. STTs in a subscriber network receive programming from the network in a downstream direction, demodulate and otherwise process that data, and output content for display on a television or other customer device. STTs also communicate data upstream to the subscriber network head end. Subscriber networks used to deliver programming content are also used to provide high speed data and other types of services to subscribers, with those other services also requiring upstream and downstream communications with devices in a subscriber premises.
Upgrade of subscriber network head ends to comply with the OCAP (OpenCable Application Platform) and DSG (DOCSIS Set-Top Gateway) specifications promulgated by Cable Television Laboratories, Inc. can result in some head ends that are no longer able to receive upstream signals from certain STTs. This is believed to be caused by subscriber premises wiring that allots approximately half of the RF signal power to cable modems and the remaining signal power among all other devices. STTs in such an environment may be unable to output enough upstream RF power to effectively communicate with the head end. One possible solution to this problem is to route upstream STT communications through a cable modem in the same premises. Indeed, many newer STTs include a MoCA (Multimedia over Coax Alliance) interface. As is known in the art, MoCA defines layer 1 and layer 2 protocols for communicating data over coaxial cable.
Although an STT could be configured to use an existing MoCA interface for upstream data communications routed through a cable modem, this could present other problems. If an STT's MoCA interface is used for upstream communications with a head end, those communications should not pass through a router in the subscriber premises. If an STT is connected to a cable modem through a router, the head end may have difficulty polling the STT. If an STT's MoCA interface is connected directly to a cable modem, however, other devices in the home may not be able to communicate to the STT. Notably, STTs increasingly include features that allow multiple STTs to network with each other and with computers and other devices in the premises (e.g., to share media in different rooms). Using an STT MoCA interface for upstream communications with the head end could thus preclude that STT from implementing certain home networking features. Although an STT could be constructed with multiple MoCA interfaces, adding hardware to implement multiple MoCA interfaces could significantly increase STT unit cost.
Networking multiple STTs through their respective MoCA interfaces also presents other challenges. As developers create more and more features that rely on an in-home MoCA-based network, those designers are less likely to be aware of other developers' efforts, and thus more likely to create features that might conflict with features of other developers' software. Although it is possible to create multiple physical channels in a MoCA RF frequency band, inter-channel interference can result.